TESK2 is a nuclear protein that belongs to the protein kinase superfamily and is expressed in testis and prostate. Functioning as a dual-specificity protein kinase, TESK2 catalyzes the ATP-dependent phosphorylation of substrates and autophosphorylation on tyrosine and serine/threonine residues, thereby mediating intracellular signal transduction pathways. TESK2 requires magnesium as a cofactor and its catalytic activity is thought to play an important role in meiotic events such as spermatogenesis. TESK2 contains one protein kinase domain that is 65% identical to the kinase domain found in TESK1 (testicular protein kinase 1), suggesting a similar role for these proteins in phosphorylation events. Three isoforms of TESK2 are expressed due to alternative splicing.